In the field of photovoltaics, high performance solar cell efficiency requires multiple and expensive processing steps to fabricate desired features in the solar cell. Such steps limit the utility of solar cells owing to added process costs.
In conventional solar cell designs, photogenerated current is driven to two electrodes: (1) a bottom (often continuous and uniform) electrode on a bottom side of the solar cell and (2) a fine printed array of wires on a front side (illuminated side) opposite to the bottom side. The fine printed array of wires on the front side of the solar cell can be formed by screen printing silver pastes into a fine pattern of lines.
Between the bottom electrode and the electrode on the front side, a conventional solar cell includes an emitter containing dopants in a semiconductive material. The emitter can be under the electrodes on the front side. Although the electrodes on the front side are patterned, in conventional solar cell designs, no such in-plane patterning is required for the dopants within the semiconductive material. A solar cell may contain regions of different doping varying through the depth of the cell from the bottom side to the front side. However, generally, within a plane perpendicular to the depth direction, dopants disperse uniformly.